Important! Why Carbon Sequestration Won't Save Us
by Michael Graham Richard, Gatineau, Canada on 07.31.06
Carbon sequestration, also known as geosequestration, seems like a good deal. "Have your carbon cake and eat it too." In principle, it works this way: You capture CO2 emissions at the source before they are released into the atmosphere, compress them until they become liquid and then inject them in deep underground holes. What could be simpler? It certainly sounds like a good tool to fight global warming while enjoying the Earth's huge coal reserves.
I used to think that it would indeed be one of the many solutions used to save ourselves from catastrophic climate change, but not anymore. In fact, I now think that it might be a counter-productive red herring. What has made me change my mind? What's the problem? Read on, please.
Tim Flannery, in his highly recommended book The Weather Makers, dedicates a chapter to engineering solutions to global warming. In it, he gives an overview of carbon sequestration technology, the problems that have to be solved before it can work, and what the coal industry has been doing so far.
Here are the problems in order:
First, from the smokestack:
The stream of CO2 emitted there is relatively dilute, making CO2 capture unrealistic. The coal industry has staked its future on a new process known as coal gasification. These power plants resemble chemical works more than conventional coal-fired power plants. In them, water and oxygen are mixed with the coal to create carbon monoxide and hydrogen. The hydrogen is used as a fuel source, while the carbon monoxide is converted to a concentrated stream of CO2. These plants are not cheap to run: around one-quarter of the energy they produce is consumed just in keeping them operating. All indications suggest that building them on a commercial scale will be expensive and that it will take decades to make a significant contribution to power production.
So about 25% of the energy they make is used just to keep them operating, they are more expensive and it will take decades (an amount of time we don't have) before they make a significant contribution. Meanwhile, old coal power plants have an average lifetime of 60 years.
What's next?
Let's assume that some plants are built and the CO2 is captured. For every tonne of anthracite [coal] burned, 3.7 tonnes of CO2 is generated. If this voluminous waste could be pumped back into the ground below the power station it would not matter as much, but the rocks that produce coal are not often useful for storing CO2, which means that the gas much be transported. In the case of Australia's Hunter Valley coal mines, for example, it needs to be conveyed over Australia's Great Dividing Range and hundreds of kilometres to the west. [pipelines cost about $1 million per mile, more when terrain is rough and uneven.]Once the CO2 arrives at its destination it must be compressed into a liquid so it can be injected into the ground--a step that typically consumes 20 per cent of the energy yielded by burning coal in the first place. Then a kilometre-deep hole must be drilled and the CO2 injected. From that day on, the geological formation must be closely monitored; should the gas ever escape, it has the potential to kill. [...]
The largest recent disaster caused by CO2 occurred in 1986, in Cameroon, central Africa. A volcanic crater-lake known as Nyos belched bubbles of CO2 into the still night air and the gas settled around the lake's shore, where it killed 1800 people and countless thousands of animals.
Okay, so even more energy is lost by compressing the CO2 to liquid form and we must monitor for leaks. What else?
Earth's crust is not a purpose-built vessel for holding CO2, and the storage must last thousands of years so the risk of leak must be taken seriously.Even the volume of CO2 generated by a sparsely populated country such as Australia beggars belief. Imagine a pile of 200-litre drums, ten kilometres long and five across, stacked ten drums high. [1.3 billion drums] Even when compressed to liquid form, that daily output would take up a cubic kilometre, and Australia accounts for less than 2 per cent of global emissions! Imagine injecting 50 cubic kilometre of liquid CO2 into the Earth's crust every day of the year for the next century or two.
If geosequestration were to be practised on the scale needed to offset all the emissions from coal, the world would very quickly run out of A-grade reservoirs near power stations and, especially if the power companies are not liable for damages resulting from leaks, pressure would be on to utilise B, C, D and E grade reservoirs.
Okay, so burying it in the ground is not so simple or safe - as the oil industry likes to remind us, drilling is expensive - and it's not a long-term solution since we will run out of convenient places to sequester the liquid CO2. Anything else?
All of this suggests that the best case scenario for geosequestration is that it will play a small role (at most perhaps 10 per cent by 2050) in the world's energy future.Because action is needed now to combat climate change, both the public and the marketplace need to see proof of geosequestration's potential. Big coal should already be building trial coal gasification plants with geosequestration as a test of the economic and technological viability of their approach. Yet, despite offers of government assistance, very little is happening with geosequestration. [...] Imagine the cost of building the new generation coal gasification power plants, the separation, storage, pipelines, compressors and injection wells.
So they're not even rushing to test it and make it happen?
Politicians have been seduced by the coal industry's spin. [...] the Australian government set up [behind closed doors] a $500 million research fund for low emission technologies, precisely tailored in its brief to accommodate geosequestration. That's half a billion dollars that will never be fairly shared between all energy options to ensure the best outcome for the nation. [...]What is at stakes is [...] that Australia must increase its power production by more than 50 per cent by 2020 (a slow rate of growth compared with China [the biggest coal user in the world]), and the coal industry would like to secure as large a share of the cake as possible.
All this talk of carbon sequestration can basically be seen as a delaying tactic, as a way to get government support and to keep the operation and construction of coal power plants more socially acceptable. It's the equivalent of saying: "Don't bother us, we're working on it!"
But even if we suppose that big coal starts to build the expensive gasification plants soon and that they can solve most of the technical problems with geosequestration, they are not saying that they want to replace old, extremely dirty plants with the new ones; they want to build new ones and keep the old ones. They almost certainly won't bear the liability of CO2 leaks from underground storage, so that's an extra cost for taxpayers, not to mention that the electricity coming from coal gasification plants that do carbon sequestration will be more expensive because a lot of energy is lost in the process of running the plants, in the actual sequestration operating, and the huge costs of building the pipelines, the plants, drilling the holes, maintenance & monitoring, etc, will be passed on to the customers (or they'll ask for subsidies - same difference).
So it'll take decades which we don't have, be extremely expensive, probably won't work that well, and we'll run out of good burying sites before long. Meanwhile, the clean energy industry (solar, wind, wave, geothermal) will keep growing very fast at exponential rates, their costs will keep going down and the efficiency of their production units (wind turbines, solar panels, hydrokinetic buoys, Gorlov helical turbines, geothermal heat pumps) will keep going up.
The fastest and cheapest way to close down coal plants soon is probably investments in efficiency. Remember, it's a lot cheaper to save a watt of electricity than to produce one.
As a society civilization species, we must back the right horse and stop being misled by the coal industry's delaying tactics. There's a big opportunity cost in time and resources to going down the wrong path. Each new power plant big coal builds means decades of fat profit for it, but for the rest of us here on Earth, it's just bad, bad news.
Read: The Weather Makers by Tim Flannery.
Listen: NPR Interview: Tim Flannery on Climate Change.
See also: ::Carbon Sequestration: Speed Bump or Wall?, ::Potential Leakage and Toxicity Problems with CO2 Sequestration
They're not done yet with the 25% and the other 20% of parasitizing the gross fuel efficiency. S02 and mercury scrubbing can take between 12 and er 25% more of the gross power output, (with conventional off the shelf technology). Some of this can be shifted to the front end with the most modern designs but it is still an expense and a significant power loss to remove those from coal no matter what.
Very long winded. I like when an article is summarized and honest upfront and explains down below. So, if they can get it to be more eficient it would be good? Here in Texas we have thousands of old wells, we could get more out of them by sequestering CO2, so it could be very good.
Also, any time we are using the earths resources, I prefer to do it locally so I can see the damage (as oposed to others who like to rape other countries). Where is all of this copper etc coming from. Much more damage is done to way more sensitive places through mining than is done through gas/coal excavation. I would love to see unbaised, informational studies done.
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editor note: Most of our posts are very short. Sometimes we have longer ones. I thought this one was important enough to deserve the extra length.
The main problem here is time and cost. We don't have that kind of time because we must act on climate change as soon as possible (and burning coal is one of the biggest contributors, along with smog, mercury emissions, etc), and since the costs of this solution would be very high, why not invest in clean technologies and efficiency instead of this band aid? There's also the problem that the spectre of "clean coal" keeps old coal plants more acceptable in people's mind because they imagine that someday their carbon emissions will be sequestered, something that is just untrue. I'm sure the pressure on the coal industry (from the public and from governments) would be greater if they didn't constantly talk about carbon sequestration. It seems counter-productive.
As for the US having a lot of oil wells, I'm not sure that old oil wells are necessarily good spots to bury CO2. Some of them probably are, but from what I've read, it takes a very specific kind geological formation and there are problems about CO2 leaking and reaching aquifers.
so how exactly does 1 ton of carbon become 3.7 tons of carbon?
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Answer: "Black coal (anthracite) is composed of at least 92 per cent carbon, while dry brown coal is around 70 per cent carbon and 5 per cent hydrogen. Carbon and oxygen--the components of CO2--are close neighbours on the periodic table, meaning that they have similar atomic weights. Because two oxygen atoms combine with one carbon atom to form CO2, around three and a half tonnes of the gas is created for every tonne of anthracite consumed."
One point left out - current coal burning technology has an efficiency of around 35% ( coal to electricity).
The efficiency of using natural gas and hydrogen is considerably higher. So even though a considerable amount of energy is used to convert the coal to CO2 and hydrogen, the hydrogen will burn much more efficently than the coal. So the numbers need adjusting.
Another note - there is a pilot plant sequestering CO2 in Canada. The CO2 Geological Storage R&D Project.
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editor note: Hmm. I'm not so sure about that. I'd have to find numbers on the efficiency of gasification plants vs. traditional plants, but I would be surprised if the former was more efficient than the latter because of all the extra processing required. I think that Mr. Flannery meant that gasification plants were 25% less efficient per amount of coal used, though compared to older coal plants they might be more efficient just because they are newer and better designed.
But if you have some data, please share it with us.
http://www.treehugger.com/files/2005/06/greenfuel_produ.php
algae seem to be good and profitable smokestake cleaning sollution
they love co2
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editor note: It's certainly an interesting mitigation solution, though they mention that 60% of CO2 is still emitted.
But a 40% cut is huge, and if the technology works and is mature, it should be retrofitted on all fossil fuel power plants. But there are questions: I wonder what the mercury and other nasties in coal emissions do to the algae? Could it contaminate the biofuels produced that way? Can this technology scale up to handle the emissions produce by big plants that burn up to 500 tonnes of coal per hour?
Thanks for reminding me about this one, Andreas!
Forgive my pedantry, but according to Calculating the Environmental Impact of Aviation Emissions (an Oxford University study):
"Combustion of one kilogram of fuel oil yields 3.15 kilograms of carbon dioxide gas. Carbon dioxide emissions are therefore 3.15 times the mass of fuel burned."
This is different enough from your 3.7 : 1 ratio to have a significant impact on calculations made using it. Do you have a source for the 3.7 figure so I can try to get to the bottom of it?
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editor note: The source for that particular number is Tim Flannery, but I've seen it in other places too.
Different fossil fuels have different number of carbon and hydrogen atoms, so when burned, they generate different amounts of CO2. Natural gas has less carbon atoms and more hydrogen ones, so it produces less CO2 by weight burned, while oil produces more, and coal even more (with anthracite producing the most).
One source is this:
http://www.eia.doe.gov/cneaf/coal/quarterly/co2_article/co2.html
Anthracite coal is from 92% to 98% carbon.
"Because the atomic weight of carbon is 12 and that of oxygen is 16, the atomic weight of carbon dioxide is 44. Based on that ratio, and assuming complete combustion, 1 pound of carbon combines with 2.667 pounds of oxygen to produce 3.667 pounds of carbon dioxide."
So it appears that 3.7 was rounded up, but was pretty close (somewhere else, "three and a half" is mentioned).
Oh, suckle me doom!
Like a mother's breast
Suckle me close
That I may writhe and moan
Like a true child of you
Right. There are no solutions but the ones you wish to dictate. As if.
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editor note: Are you for real? I'm experiencing cognitive dissonance reading your comment. You are totally missing the point.
Until recently, I thought carbon sequestration would work well and help us substantially. It is by reading about it and looking at the evidence (are you impermeable to evidence? do you know things we don't? did you even read the post?) that I became convinced that it was a misallocation of time and resources, things we don't have in excess, and that we could more efficiently and durably address problems with other solutions.
I'm not any more than you in a position to "dictate" solutions, but like you, I can share what I learn and have an opinion on things. Not all solutions that are proposed are equal, that's why we have to take a closer look and not trust that things will always be done in the best interest of all. If you disagree with me on particular points and have substantive arguments to make, go ahead.
Granted, you're probably just trolling for attention, so I will stop this here.
given the potentially serious consequences of burying CO2, why not instead sink it into plants that can be either used for food stock or biofuel source?
imagine a coal burning plant that can extract CO2 and send it to an on-site greenhouse that grows a secondary fuel source.
is there anything like that in existence?
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editor note: There's this, but as I said in a comment above, it's not quite clear yet how well it can scale and if it deals with the contamination of the resulting biofuels with things like mercury.
In the book excerpts above, it is mentioned that we would be burying 50 cubic kilometres/day of liquid CO2. That's liquid, so it's even more when gaseous. You'd need a heck of a lot of bioreactors to process that much CO2 every day, with more being produced if new coal plants keep getting built.
But the REAL problem with that is you're only delaying the release of the CO2 in the atmosphere, not stopping it. If you make biofuels from coal emissions, you're taking part of the carbon from the fossil fuel, putting it in the biodiesel, which you then burn, releasing the carbon in the atmosphere.
This is exactly the tactic used by the tobacco companies when they introduced filters. Fudged science as a delaying tactic.
"given the potentially serious consequences of burying CO2, why not instead sink it into plants that can be either used for food stock or biofuel source?"
But how would this sequester the CO2? To pull CO2 out of the atmosphere, it has to either be maintained in a permanent biomass greater than the biomass before sequestering ( such as permanent reforestization, but this can only go so far), or it has to near-permanantly be removed from the environment in a manner similar to fossilization.
Uh, don't plants _use_ CO2? You know, photosynthesis, CO2 into food for the plants, oxygen for us to breathe? ;)
And what about that nano-tech carbon-fiber ribbon y'all reported on some time ago? Why not use that supposedly inexpensive method to produce carbon fiber as a way of sequestering carbon? And, again, we'd get more oxygen out of it. Sure, it takes energy, but if we are also to believe that there is more offshore wind-potential out there than all of our current electricity needs, why not use that energy to sequester instead of simply "burying" the problem? If we can get such large, "clean" power generators on the grid soon, we can start shutting down these coal plants permanently. I'd certainly like to see the demise of mountaintop-removal mining.
Greeting. Great discussion about geosequestration. For different reasons, I have to agree with the author that may be a very bad idea. Have a look at the article in Vol. 34, No. 7, pp. 577-580 in Geology Magazine (July 2006). The article reports the findings of a group monitoring a CO2 storage borehole well in the South Liberty Oil Field near Dayton, Texas. They found that the 1,600 tons of CO2 that was pumped into a 24 meter thick sandstone layer 1500 m below ground resulted in a rather nasty alkaline brew that has been disolving the surrounding minerals and eating at the carbonate containing the stored CO2.
In other words, it is disolving its containment area and in theory, could eat its way into the water table.
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Note from the author: Hi Michael. That's another troubling finding, yes. For those who don't subscribe to Geology Magazine, I wrote a post about it here.
http://www.physorg.com/news65284632.html
Scientists are about to test microscopic sieves that trap environmentally destructive greenhouse gases before they escape coal-fired power stations and refineries.
The new gas separation technology can be fitted to existing power stations and petrochemical plants to produce hydrogen, a clean energy carrier, and capture carbon dioxide, a greenhouse gas that worsens global warming.
http://www.greencarcongress.com/2005/12/metalorganic_fr.html
MOF-177 soaks up 140% of its weight in CO2 at room temperature and reasonable pressure (32 bar).
A storage tank filled with MOF-177 could store as much CO2 as would be stored in nine tanks that do not contain MOFS. By comparison, a tank filled with porous carbon�one of the current state-of-the-art materials for capturing CO2 in power plant flues�would hold only four tanks worth of CO2.
MOFs can be made in large quantities from low-cost ingredients, such as zinc oxide and terephthalate, which is used in plastic soda bottles. And finding effective, low-cost ways of reducing CO2 emissions is crucial, according to Yaghi.
http://www.lanl.gov/news/releases/archive/02-028.shtml
The air is passed over an extraction agent, for example a solution of quicklime, the active agent in some cement. As the air passes over the extraction structure, the carbon dioxide in the air reacts with the quicklime and becomes converted to calcium carbonate (limestone), a solid that forms and falls to the bottom of the extractor.
The calcium carbonate is then heated to yield pure carbon dioxide and quicklime, which is recycled back into the extractor. The purified and liberated carbon dioxide can then be sequestered as a gas by direct injection into the ground or it could be reacted with minerals to form a solid. Carbon dioxide gas also can be sold commercially to the petrochemical industry, which uses large quantities of it to extract fossil fuels. Of course, because the process uses existing air, it does not need to be located near any particular elevated source of carbon dioxide. It captures carbon dioxide from all sources by harnessing wind as a no-cost transportation vector.
http://news.bbc.co.uk/2/hi/science/nature/5083222.stm
Carbon dioxide can be formed into a solid, such as dry ice, by cooling and squeezing. However, even in this solid form, the molecules resist linking up with their neighbours and remain as discrete units.
Simulations, though, had suggested that given the right conditions these molecules could be persuaded to join hands and form glass-like materials.
Extreme pressure
Recently, scientists in California coaxed carbon dioxide molecules to form a solid network by applying extreme pressure at high temperatures.
Their discovery could lead to a way of storing or disposing of carbon dioxide gas, a major contributor to global warming, deep in the Earth's interior.
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editor note: Interesting stuff. I had read about most of those, but I'm sure not everybody here did, so thanks for doing the research. It's good to have them in a centralized spot. I might do a post on them.
Certainly stuff to keep an eye on as it is developed, though most run into the same kind of problems as direct liquid CO2 sequestration (need for expensive gasification plants, old plants problematic, need to deal with 50+ cubic kilometers liquid CO2 equivalent per day, takes a long time to develop, opportunity cost of investing in those vs. efficiency & renewables that are less problematic, even if developed and works, with rising fossil fuel prices + sequestration prices, might not be economically competitive, etc).
There are different kinds of carbon sequesteration as other posters have pointed out. Algae is one, forests are another. But most importantly there is the soil.
I was turned onto this solution by Paul Hawken in his book Natural Capitalism where he states that if the world's soil were returned to a healthy state, all the carbon in the atmosphere could be absorbed. The solution then, to me at least, lies in promoting the health of the world's soil.
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editor note: Certainly, though the problem with fossil fuels is that you are putting carbon in the atmosphere that hasn't been there for millions of years. So even if you were to bring back the Earth's eco-systems to pre-industrial state, you'd still have more carbon than you had then, because at that point fossil fuels were underground.
I have to agree with the author of this article. At first, the quick answer is to bury it and forget it but less we forget that whole "circle of life symba" will come back one day to bite us in the backside. We as a society simply think that if we bury it, we will be done with it. The earth is always expanding and contracting and changing. I hate to think that we are so ignorant as to think that we can build something that will never let these harmful elements into our environment again. I remember Russia thought that they built an impenetrable fortress. Too bad Chernobyl didn't quite go as planned. BTW, those pictures are seriously disturbing - especially that first one.
"Fixed fortifications are monuments to mans stupidity" - George Patton
Since plants are able to turn CO2 into oxygen and carbon, it seems like it would be possible to build a CO2 converter out of genetically optimized plants that the C02 could be passed through on the way out. There obvously would be a lot of byproduct and it would cost a lot of energy. Has anyone read anything about this kind of research?
To "peteathome's" comment regarding the efficieny of coal-fired vs gas-fired plants, I agree. Modern natural gas plants typically run on a combined-cyle system, with up to 55% of the heat energy being converted to electricity. Coal can only be burned in a single cycle, and the ultimate efficiency is limited to around 35%.
The first cyle of a combined-cyle plant is simply a jet engine turbine. Natural gas burns well in a turbine, but I am sure any stationery engineer would agree that trying to inject and burn coal dust in a turbine would rapidly destroy the turbine blades. Hence, no first cycle for coal.
'sigh' - even when faced with the evidence, people always want the magic techno-bullet.
Two problems with the author's initial assumptions.
1) Coal Burning Power plants are seldom located near the fuel source. Most of the Coal comes form WV, and Wyoming, with some other hot spots. Extremely few power plants are co-sited with the actual mining operations, instead they are closer to the point of electrical consumption. So using the mines as storage typically wouldn't work.
2) Gassifications main aim is 2-fold. One is to utilize the waste heat from the turbine sections to do usefull work, this enables them to DRASTICALLY up the thermal efficiency of the process. Two, it uses a natural gas fired turbine instead of a steam (boiler) fired setup. Why is that important? Becuase the emissions from a gas fueled turbine are greatly reduced, with very little particulate emissions compared to a coal fired boiler.
Also a gassification system can burn a wide variety of fuels. Biomass, coal, garbage, old tires, etc. It's not limited to "coal" as a fuel.
So you use the waste heat to get the efficiency up, and to process the coal in your "gassifier", this brings your efficiency up from 60% for a traditional rankin cycle steam turbine to over 75%. You actually combust a cleaner fuel, and your waste stream is cleaner. Your bulk of the carbon is contained in... the leftover coal, which is reduced to charcoal in the gassifier.
You really should do a bit of research into thermodynamics and how steam turbines work versus gas turbines... it'd be an interesting comparison.
Typical Steam turbine thermal efficiency (for most plants)= 25-40% depending on type
With better heat management this can rise to almost 60%, but most powerplants in the US aren't this efficient.
If they go to co-generation and use the waste heat for another process (co-sited with industry, building heat, municipal hot water, etc.) the efficiency goes up to 75-85%.
To give gassification a black eye because it can use coal as fuel is like giving a prius a smackdown for using gasoline.
There's some truth in this article, but also a few questionable statements. I've read Flannery's book, and think it was excellent in the main, but his analysis of the sequestration issue is a little off the money.
There's a staggering volume of suitable storage available for sequestration of CO2. Yes, the quantities coming out of the world's coal-fired power stations are beyond comprehension, but so are the potential sites for sequestering it. The IPCC has reported on this previously in its TAR.
The comments about efficiency reductions are in the right ballpark, but a couple of things need to be considered. First of all, this technology is new, and the opportunity to improve it is therefore large. Consider the improvement in electricity generation by wind turbines over the last 20 years. Second of all, the parasitic load for NOx and SOx control are already factored into the current breed of plant, so this does not need to be added in again.
The comments about gas turbine combined cycle on coal are just wrong, I'm sorry. While it is true that you can't combust coal dust in a gas turbine, you can gasify coal and burn the resulting syngas (effectively Hydrogen and CO2) through the gas turbine, with the hot exhaust used to raise steam and drive a steam generator as with a normal GTCC process.
The partial pressure of CO2 in syngas is much higher than it is in combustion products, making it much easier to capture. This is called pre combustion decarbonization, and it has been working on an industrial scale (although not on a utility scale) for many years.
But perhaps most importantly, it is too difficult to say in this discussion whether or not carbon capture and storage will be economic. Coal is one of the cheapest fuels known. What effect will the addition of air separation units, gasification plants and MEA scrubbers have on the levelized cost of electricity? Certainly it will be more expensive, but how much more expensive? Right now, we just don't know, but it looks as if it might still be economic. Until somebody builds a few of these plants, we won't know for sure.
In the meantime, let's keep working to improve and expand the renewable energy portfolio and make everything as efficient as possible so that we've hedged our bets. In the end, with the assistance of an appropriate carbon price signal, the market will work out which technologies win the race.
http://www.csmonitor.com/2006/0111/p01s03-sten.html
Even though it's early yet, and may be a long shot, "the technology is quite fascinating," says Barry Worthington, executive director of US Energy Association in Washington, which represents electric utilities, government agencies, and the oil and gas industry.
(...)
Greenfuel isn't alone in the algae-to-oil race. Last month, Greenshift Corporation, a Mount Arlington, N.J., technology incubator company, licensed CO2-gobbling algae technology that uses a screen-like algal filter. It was developed by David Bayless, a researcher at Ohio University.
A prototype is capable of handling 140 cubic meters of flue gas per minute, an amount equal to the exhaust from 50 cars or a 3-megawatt power plant, Greenshift said in a statement.
For his part, Berzin calculates that just one 1,000 megawatt power plant using his system could produce more than 40 million gallons of biodiesel and 50 million gallons of ethanol a year. That would require a 2,000-acre "farm" of algae-filled tubes near the power plant. There are nearly 1,000 power plants nationwide with enough space nearby for a few hundred to a few thousand acres to grow algae and make a good profit, he says.
Energy security advocates like the idea because algae can reduce US dependence on foreign oil. "There's a lot of interest in algae right now," says John Sheehan, who helped lead the National Renewable Energy Laboratory (NREL) research project into using algae on smokestack emissions until budget cuts ended the program in 1996.
In 1990, Sheehan's NREL program calculated that just 15,000 square miles of desert (the Sonoran desert in California and Arizona is more than eight times that size) could grow enough algae to replace nearly all of the nation's current diesel requirements.
"I've had quite a few phone calls recently about it," says Mr. Sheehan. "This is not an outlandish idea at all."
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editor note: As we've said above, making biofuels is nice, but it doesn't sequester carbon and doesn't slow down global warming. Not to mention that scaling biofuels generation to the treatement of anything close to amount of coal plants we have now is a challenge.
I’ve found this article and subsequent discussion very interesting and for what it’s worth thought I’d add my pennies worth to the debate.
As a reservoir engineer in the gas industry I feel moderately well placed to make some remarks concerning long term geological storage of CO2 underground. A common conception of this form of storage is that there is a large degree of risk associated with the CO2 leaking to surface. I would argue that this is not necessarily the case and will limit my reasoning to the example of CO2 being sequestered in abandoned oil and gas reservoirs.
If we take an oil or gas reservoir that is approaching abandonment the reservoir itself has the spare capacity for storage due to the space freed up through the removal of hydrocarbons. In addition, due to the work done and the data collected on the field during its producing life there is generally a very good understanding of its capacity and extent. Allied to this is the fact that the wells required for injection are already in place (no need to spend more cash on drilling new ones) along with many of the other associated bits of equipment necessary. Finally and probably most importantly we know beyond all doubt that the reservoir is an effective trapping and storage medium due to the fact that the hydrocarbons that were extracted have remained in place without leaking away for millions of years prior to its discovery.
Having said this I would point out, as has been mentioned previously, that there seems to be uncertainty over the possible chemical interaction of CO2 with the reservoir formations. Although, as with all new technology, as the understanding of the processes involved improves then mitigating steps can and will be developed.
Finally I would like to draw attention to the unique opportunity for CO2 sequestration that exists in some areas of the world. In the UK, for example, the North Sea production of oil and gas is in decline. As such there is a massive oil and gas infrastructure network comprising of reservoirs, wells, platforms and pipelines to shore that is up for decommissioning in the future. In my mind this is a ready made opportunity to utilise all these components necessary for CO2 sequestration, in conjunction with the UK’s large east coast fossil fuel power stations, while they are still in place and available.
As someone pointed out to me recently the issue of reducing greenhouse gas emissions is like a pie. There’s not one technology that is going to come along and mitigate the entire issue (the numbers and volumes involved are simply too mind boggling). Instead different technologies, be they wind, solar, sequestration or nuclear, will account for one ‘slice’ of the greenhouse gas emissions pie. As I see it the Chinese are likely to burn their vast coal deposits regardless. If it is possible that the west can develop a technology that could limit the emissions associated with this process I think it would be churlish to discount it.
Thanks for your time.
CO2 sequestering is much simpler than all this. Their are millions of old oil fields with plugged wells that can be re-drilled cheaply and have perfect reservoirs for holding CO2. Oil companies have been injecting CO2 as a compressed gas into them for decades for enhanced oil recovery with no leaks or problems. A device that turns in the wind has been invented that catalytically recovers CO2 from the atmosphere and concentrates if for compressing. This system could be setup anywhere. You just have to convince the wealthy oil companies to spend some cash to do it on a widespread basis, like all over the earth now. An easier way to sequester CO2 is to stop wetland draining in the upper midwest that is now accellerating due to Ethanol production and start restoring these wetlands instead. Thank You. Neal
Sequestration doesn't make much sense to me, fossil fuels have no place in the future energy equation. It's too inefficient, there's too much CO2, and seems like such a waste when we have all of these other energy sources (including negawatts) available. With nuclear, everyone is concerned about the radioactive waste, and while it is certainly dangerous we would not be producing anywhere near 50 cubic kilometers of it per day (not even that much nuclear waste has been yet produced, just because that's a HUGE volume) With fuel recycling, the nuclear waste production can be very small. If I had to pick between the two, I'd pick nuclear over fossil plants doing sequestration in a heartbeat. Nuclear is no fix-it-all either, but certainly better than fossil fuels.
Coal-To-Liquids technology is being lauded, especially by Big Coal in the U.S. Sequester the CO2 from 200 million personal cars flying around on the interstates at 90 miles per hour? YEAH!
What a fascinating discussion!
Two comments.
First no-one has mentioned the solution identified by James Lovelock of combining carbon dioxide with a powder made from an alkaline igneous rock called serpentine. You just let the CO2 rip into the air and site your operation near the rock deposit. The result is magnesium carbonate, "a stable solid that could in part be used as a building material and is easy to store..."
Not sure of it's practicality or mass potential.
Second, an alternative clean energy just emerging is "hot rocks". We have them in abundance here in Australia. Not sure about the rest of the world. You can read about it here.
On the topic of pH changes and dissolution compromising seal integrity (i.e. causing leaks); this issue will only be relevant when you are attempting to sequester CO2 in carbonate reservoirs where a large component of the rock matrix is CaCO3 and easy to dissolve.
The majority of current pilots are not considering these types of formations. More specifically - the Frio pilot you discuss is an unconsolidated sandstone aquifer (mostly quartz, SiO2) while the top seal is an impermeable shale. Changes in fluid pH will not significantly modify the permeability of the seal.
In my opinion, CO2 sequestration should be viewed as a stop-gap measure to quickly reduce carbon emissions while bringing carbon-neutral energy sources on-line. Technologically, sequestration is relatively straight-forward to implement (assuming you can afford the added energy cost), and contrary to the opinions voiced in this blog, years of comprehensive flow modeling and oil field EOR work suggest that the chance of leakage through the formation at the depths being considered (vs. well bore failure) are very small. Additionally, CO2 is not a poison - it takes VERY high CO2 concentrations to cause injury or death (remember - suffocation) making the impact of an unlikely small scale leak easy to mitigate. Although there are a couple of documented cases of death due to geologic CO2 out-gassing, this type of hazard is small in comparison to the harm implicit in large scale global climate change - it only takes one extra hurricane to kill 1000 people.
What's missing from the picture are strong economic incentives for power producers to start sequestering on a large scale i.e. a carbon tax. This in turn will make wind, geothermal, and other carbon-neutral energy sources more competitive in the national power market.
EnPro process is the unique solution to global warming. Sequestration is not!!!
By
Dr. O CHAALAL
Global warming is the a-la-mode political-scientific apple pie of the so-called civilized world. The warnings from Montreal are dire as scientists and politicians agree that global warming is upon us [1], [2].
While we are suffering from sunstrokes, tempers flare in the heat of the night and crime is on the rise in the Third World. In fact, global warming is more harmful to developing countries, because they are poorer and therefore more vulnerable to the effects of climate change. Planting crops in barren fields is not only a waste of time but also an insult to the poor, dying from starvation as a result from the pollution enveloping his world, a pollution for which the industrialized countries are the only responsible parties.
However, there is a ray of sunshine that is piercing the doom and gloom of unchecked climate change and that is the transformation of carbon dioxide into solid material. Such process binds carbon dioxide and converts it into stable by-products such as fertilizers and water for irrigation.
Some would argue that global warming caused by CO2 is a dragon about to be unleashed upon the planet. If they are right, then the Kyoto Protocol is no more than a cover of a funny and ridiculous UN textbook edited by the 189 signatories to the UN Climate Change Convention in Montreal.
What really amazes me is that some people in Montreal think that the best way to stop global warming is to jail the chemical compound that is responsible for making nature angry [3]. They have advanced a solution known as “sequestration,” which is equivalent to locking the demon carbon dioxide in a box and throwing away the key. Capturing carbon dioxide and burying it as an active devil, is not practical or reliable. How does one contain a diffusive gas- Another problem with Sequestration and Capture is the hidden costs. The costs to bury carbon dioxide today would be enormous. To bury a ton of carbon dioxide costs more than $100. And you don’t need to be a mathematician to figure out how much it would cost to bury the millions of tons of CO2 that are currently polluting our mother earth.
Because of the inherent risks associated with the sequestration process, no scientist can (or will) take the responsibility to say that the porous rock located few hundreds feet deep in the earth can hold the carbon dioxide. No one knows whether the carbon dioxide will stay underground. Any scientist will tell you that the recalcitrant prisoner might bubble through cracks in the earth’s crust. It may come back; carrying with it yet other unknown gases into the water table and further pollute our resources, or resurface and permeate the atmosphere once again. Chemical and mechanical engineers thoroughly understand this phenomenon, which relates to the transport of gaseous material through porous media.
James C. Orr, researcher at the Laboratoire des Sciences du Climat et de l'Environnement/ Commissariat a l'Energie Atomique in Gif sur Yvette, France, was right when he addressed the question of how long the injected CO2 might stay isolated from the atmosphere. In a scientific explanation, Orr was saying that the demon could escape from the temporary cell we offered it. The process is called “gradual leakage of carbon dioxide back into the atmosphere.” Orr is currently coordinating a project called GOSAC (Global Ocean Storage of Anthropogenic Carbon)
On the other hand, UN estimates that half the amount allocated to the Kyoto Protocol could permanently solve all of the world's major problems: it could ensure clean drinking water, sanitation, basic health care, and education for every single person in the world now. Is it illusion, reality or a dream-
We are in the year 2006 and the signs of climate change are visible to the world. From super typhoons to mega hurricanes, like John and the erratic behavior of hurricane Ernesto to a small mountain village where temperature spikes such as 30oC to 10oC in twenty-four hours and then back up to 30oC are not normal for this time of year.
Severe water shortages, droughts, raging forest fires, extreme pollution levels and decreasing oil supplies all paint a negative model of today’s world. Politicians scratch their heads in frustration; economists make dire predictions of the coming of dark ages while oil prices climb to $200/barrel. The every day Joe pays the price both in being gouged at the gas pumps and stressed out by fear mongers or shot and killed by rogue military units spurred on by lust for power and greed.
Meanwhile, nobody listens or supports the scientists who are screaming in alarm and working feverishly to counteract the rising CO2 levels. Increasing CO2 levels are due to pollution levels caused by industrialists and unscrupulous and daily use of hydrocarbon fuels.
My conclusion is that “The carbon dioxide should not be sequestered, jailed or injected into our ailing earth, but transformed into useful products such as water for irrigation and other valuable chemical products that can be used as fertilizers.” EnPro process ( www.enpro.no), is unique solution to the global warming problem.
I hope that this genius process transforms the desert to a green garden or even to a forest. Hence, the trees will be more responsible than any honest politician will. The trees are capable of transforming the carbon dioxide and providing a natural solution to global warming – Let the trees do the job.
References
1. Stevens, S. H.; Kuuskraa, V. A.; Spector, D.; Riember, P. CO2 Sequestration in Deep Coal Seams: Pilot Results and Worldwide Potential. Presented at the Fourth International Conference on GHG Control Technologies, Interlaken, Switzerland, Aug. 1998.
2. Gunter, W. D.; Gentzis, T.; Rottenfusser B. A.; Richardson, R.J.H. Energy Convers. Mgmt. 1997, 38 (Suppl.), S217-S222.
3. Adams, E.; Akai, M.; Golmen, L.; Haugan, P.; Herzog, H.; Masuda, S.; Masutani, S.; Ohsuma, T.; Wong, C. S. An International Experiment on CO2 Ocean Sequestration. Presented at the Fourth International Conference on GHG Control Technologies, Interlaken, Switzerland, Aug. 1998.
As a former reservoir/production enhancement engineer in the oil and gas industry and currently an environmental engineer, I must agree with what Chris and Jonathan Ajo-Franklin posted. Everybody agrees (or should) that we have a serious problem on our with GHG's. Most people agree that we need a solution to the problem NOW rather than later....Carbon sequestration is the most economical and readily available short term solution. And by short term, I mean decades to centuries. Carbon sequestration gives us the "buffer" time to reduce emissions emitted to the atmosphere while indroduce IGCC plants, wind power, and solar at a larger scale. Throughout the history of mankind, we have always fixed a current problem by some means and then found out where we may have made mistakes in the process. We ALWAYS learn as we go. Everybody stating solutions other than sequestration have VERY valid points, but none of their solutions can be integrated as fast and be as economically feasable RIGHT NOW. There may be a better way to reduce carbon dioxide emissions rather than burying it such as EnPro discussed. If people want to see results right now, carbon sequestration is the best option. This will give us the time we need to become more efficient at the processes we use in our coal-fired power plants, make solar and wind more economical, etc., while getting rid of as much CO2 as we can.
It may be worth you all checking out the Big Sky Carbon Sequestration Partnership. Review their presentation, it is quite informational.
http://www.bigskyco2.org/
Thank you for your time.
The credibility of the author quoted is in serious doubt due to his inability to do simple calculations.
The annual CO2 emissions from Australia are 376Mt/yr:
http://www.iaea.org/inis/aws/eedrb/data/AU-enem.html
This approximates to 1 million tonnes per day.
The density of liquid CO2 is 1003kg (~1 tonne) per cubic metre:
http://www.wessingtoncryogenics.co.uk/CO2%20Data%20Sheet.pdf
Therefore the volume of CO2 produced by Australia daily is approximately 1 million cubic metres.
The third root of 1 million is 100.
Therefore the daily volume of liquid CO2 from Australia would occupy a 100m cube, not a 1000m cube as quoted by the author.
The author overstates the volume of liquid CO2 by a factor of 1000.